The long-term success of dental implants is established by literature. Although clinically well defined, the complex genetic pathways underlying osseointegration have not yet been fully elucidated. ...Furthermore, patients with osteopenia/osteoporosis are considered to present as higher risk for implant failure. Porous tantalum trabecular metal (PTTM), an open-cell porous biomaterial, is suggested to present enhanced biocompatibility and osteoconductivity. The goal of this study was to evaluate the expression patterns of a panel of genes closely associated with osteogenesis and wound healing in osteopenic patients receiving either traditional titanium (Ti) or PTTM cylinders to assess the pathway of genes activation in the early phases of osseointegration.
Implant cylinders made of Ti and PTTM were placed in osteopenic volunteers. At 2- and 4 weeks of healing, one Ti and one PTTM cylinder were removed from each subject for RT-PCR analysis using osteogenesis PCR array.
Compared to Ti, PTTM-associated bone displayed upregulation of bone matrix proteins, BMP/TGF tisuperfamily, soluble ligand and integrin receptors, growth factors, and collagen genes at one or both time points. Histologically, PTTM implants displayed more robust osteogenesis deposition and maturity when compared to Ti implants from the same patient.
Our results indicate that PTTM properties could induce an earlier activation of genes associated with osteogenesis in osteopenic patients suggesting that PTTM implants may attenuate the relative risk of placing dental implants in this population.
Objectives. The use of drug delivery systems in dentistry is a relatively new area of research with the exception of fluoride ion release from polyalkenoate cements and their predecessor silicate ...cements. The present study is based on the use of a bio-compatible material ethylene vinyl acetate copolymer (EVA) that enables constant release of drugs of therapeutic levels over extended periods of time at doses suitable for the treatment of oral conditions.
Method. Polymer casting solutions were made by dissolving EVA and the drug in the ratio of 40:1 in 70 ml of dichloromethane at 38 °C for 6 h. Thin square films of 3×3 cm
2 with a thickness of 1 mm were cut from the dry sheet obtained by solvent evaporation technique. Drug loaded samples were extracted for a minimum of 14 days in 10 ml medium (double distilled water or water/ethanol (4:1)) which was replaced daily. Spectral measurements were made to follow changes in optical densities (OD) during release kinetics. Effect of temperature (24 and 37 °C) on the rate of drug release was studied and the energies of activation (Δ
E
≠) were calculated using Arrehenius equation for the diffusion (translocation) of molecules of tetracycline hydrochloride (TTH), doxycycline hydrochloride (DOH), and chlorhexidine diacetate (CDA) in water as extracting medium. Effect of extracting medium (water and water/ethanol (4:1)) was also investigated on the rate of drug release measurements at 24 °C.
Results. Analysis of variance of the data revealed that significantly enhanced rates were observed at the higher temperature (37 °C) and when extracting medium was changed to water/ethanol (4:1) for TTH, DOH and CDA (
p<0.0015). The enhanced rate values seem to be due to the formation of channels in the polymer. The largest activation energy (21.83
kcal
mol
−1) observed for CDA was interpreted as due to the highest average molecular weight (626) compared to TTH (481) and DOH (481).
Significance. These in vitro rate of drug release measurements will provide a basis for establishing a novel approach (treatment modality) for sustained intra-oral drug delivery over extended time periods using laboratory methods and materials that are readily available to dentists.
Periodontitis is a primarily bacterial infection that is common in dentate individuals, while denture stomatitis is a predominantly fungal infection that is common among denture wearers. Both ...infections may increase a patient's risk for chronic systemic infection dissemination, and may in turn increase the risk of chronic, inflammatory-based systemic diseases. Systemic diseases for which chronic oral infections are believed to confer attributable risk include atherosclerotic and coronary disease, stroke, chronic obstructive pulmonary disease, diabetes, and hypertension. It appears that invasive oral pathogens trigger a systemic inflammatory response via mediators released by the cardiovascular system and liver, putting the patient at increased risk for these diseases. Data comparing gene expression between denture wearers with and without denture stomatitis (and associated Candida albicans infections) has demonstrated unique up- and down-regulation patterns for a number of genes. It appears that down-regulated genes (whose functions are thereby diminished) are associated with reduced epithelial barrier integrity. By contrast, there appears to be an association between up-regulated genes (which have enhanced function) and inflammatory responses that facilitate the ability of C. albicans to bind with and penetrate the oral mucosa. Molecular biological approaches suggest that future therapeutic development could target reducing either the local inflammatory processor, the binding and attachment of C. albicans to the oral mucosa, or both. Ongoing investigations are attempting to incorporate interventions into matrices, to provide a local and sustained presence to therapeutic interventions.
Background: In Alabama, low birth weight (LBW) infants are about 20 times more likely to die before their first birthday compared to normal birth weight infants. While the rate of LBW has been ...consistently higher among African Americans compared to whites, there has been a gradual increase in LBW for both African Americans and whites over the last 15 years. In an attempt to identify modifiable risk factors for LBW, we have previously reported that a pregnant woman's poor periodontal health may be an independent risk factor for low birth weight.
Methods: A predominantly African American and socioeconomically homogeneous group of 448 women was followed from the second trimester of their first pregnancy. Thirty‐nine LBW cases were observed at the end of follow‐up. Using 17 preterm LBW cases and 63 randomly selected controls from the above cohort, the periodontal pathogen‐specific maternal serum IgG levels during the second trimester of pregnancy were evaluated in relation to birth weight of the infant, while controlling for known risk factors for LBW.
Results: Porphyromonas gingivalis (P.g.)‐specific maternal serum IgG levels were higher in the LBW group (mean 58.05, SE = 20.00 μg/ml) compared to the normal birth weight (NBW) group (mean 13.45, SE = 3.92 μg/ml; P = 0.004). Women with higher levels of P.g.‐specific IgG had higher odds of giving birth to LBW infants (odds ratio OR = 4.1; 95% confidence interval CI for odds ratio = 1.3 to 12.8). This association remained significant after controlling for smoking, age, IgG levels against other selected periodontal pathogens, and race.
Conclusions: Low birth weight deliveries were associated with a higher maternal serum antibody level against P. gingivalis at mid‐trimester. J Periodontol 2001;72:1491‐1497.
Background: Periodontitis is an inflammatory condition of toothsupporting tissues that is usually treated by mechanical removal of plaque and microorganisms that adhere to teeth. This treatment, ...known as scaling and root planing, is not optimally effective. Adjunctive therapy with locally delivered antimicrobials has resulted in improved clinical outcomes such as probing depth reduction. This article reports on the efficacy and safety of locally administered microencapsulated minocycline.
Methods: Seven hundred forty‐eight (748) patients with moderate to advanced periodontitis were enrolled in a multi‐center trial and randomized to 1 of 3 treatment arms: 1) scaling and root planing (SRP) alone; 2) SRP plus vehicle; or 3) SRP plus minocycline microspheres. The primary outcome measure was probing depth reduction at 9 months. Clinical assessments were performed at baseline and 1, 3, 6, and 9 months.
Results: Minocycline microspheres plus scaling and root planing provided substantially more probing depth reduction than either SRP alone or SRP plus vehicle. The difference reached statistical significance after the first month and was maintained throughout the trial. The improved outcome was observed to be independent of patients’ smoking status, age, gender, or baseline disease level. There was no difference in the incidence of adverse effects among treatment groups.
Conclusions: Scaling and root planing plus minocycline microspheres is more effective than scaling and root planing alone in reducing probing depths in periodontitis patients. J Periodontol 2001;72:1535‐1544.
Abstract Campylobacter species ( C. jejuni , C. fetus ) are enteric abortifacient bacteria in humans and ungulates. Campylobacter rectus is a periodontal pathogen associated with human fetal exposure ...and adverse pregnancy outcomes including preterm delivery. Experiments in pregnant mice have demonstrated that C. rectus can translocate from a distant site of infection to the placenta to induce fetal growth restriction and impair placental development. However, placental tissues from human, small-for-gestational age deliveries have not been reported to harbor C. rectus despite evidence of maternal infection and fetal exposure by fetal IgM response. This investigation examined the temporal relationship between the placental translocation of C. rectus and the effects on fetal growth in mice. BALB/c mice were infected at gestational day E7.5 to examine placental translocation of C. rectus by immunohistology. C. rectus significantly decreased fetoplacental weight at E14.5 and at E16.5. C. rectus was detected in 63% of placentas at E14.5, but not at E16.5. In in vitro trophoblast invasion assays, C. rectus was able to effectively invade human trophoblasts (BeWo) but not murine trophoblasts (SM9-1), and showed a trend for more invasiveness than C. jejuni. C. rectus challenge significantly upregulated both mRNA and protein levels of IL-6 and TNFα in a dose-dependent manner in human trophoblasts, but did not increase cytokine expression in murine cells, suggesting a correlation between invasion and cytokine activation. In conclusion, the trophoblast-invasive trait of C. rectus that appears limited to human trophoblasts may play a role in facilitating bacterial translocation and placental inflammation during early gestation.
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